<template>
	<view>
		<my-search></my-search>
		<view class="scroll-view-container">
		      <!-- 左侧的滚动视图区域 -->
		      <scroll-view class="left-scroll-view" scroll-y :style="{height: wh + 'px'}">
				<view :class="['scroll-item', i === active ? 'active' : '']" v-for="(item,i) in firstList" :key="i" @click="changeActive(i)">
					{{item.cat_name}}
				</view>
		      </scroll-view>
		      <!-- 右侧的滚动视图区域 -->
		      <scroll-view class="right-scroll-view" scroll-y :style="{height: wh + 'px'}" :scroll-top="scrollTop">
		        <view class="cate-lv2" v-for="(item2,i2) in secondList" :key="i2">
					<view class="cate-lv2-title">{{item2.cat_name}}</view>
					<view class="cate-lv3-list">
						<view class="cate-lv3-item" v-for="(item3,i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
							<image :src="item3.cat_icon.replace('dev','web')"></image>
							<text>{{item3.cat_name}}</text>
						</view>
					</view>
				</view>
		      </scroll-view>
		    </view>
	</view>
</template>

<script>
	export default {
		data() {
			return {
				firstList: [],
				secondList: [],
				wh: 0,
				active: 0,
				//滚动条距离顶部的距离
				scrollTop: 0
			}
		},
		onLoad() {
			this.getHeight()
			this.getCateList()
		},
		methods: {
			//得到分类数据
			async getCateList() {
				const { data: res } = await uni.$http.get('/api/public/v1/categories')
				if(res.meta.status !== 200) return uni.$showMsg()
				console.log(res)
				this.firstList = res.message
				this.secondList = res.message[0].children
			},
			//计算窗口的剩余高度
			getHeight(){
				this.wh = uni.getSystemInfoSync().windowHeight
			},
			changeActive(index){
				this.active = index
				//改变active后重新为二级菜单赋值
				this.secondList = this.firstList[index].children
				// this.scrollTop = 0
				this.scrollTop = this.scrollTop ? 0 : 1
			},
			//点击三级分类跳转到商品列表页
			gotoGoodsList(item){
				uni.navigateTo({
					url: '/subpkg/goods_list/goods_list?cid=' + item.cat_id,
				});
			}
		},
	}
</script>

<style lang="scss">
	.scroll-view-container {
	  display: flex;
	
	  .right-scroll-view{
		  background-color: #fff;
	  }
	  
	  .left-scroll-view {
	    width: 120px;
	
	    .scroll-item {
	      line-height: 60px;
	      background-color: #f7f7f7;
	      text-align: center;
	      font-size: 14px;
	
	      // 激活项的样式
	      &.active {
	        background-color: #ffffff;
	        position: relative;
	
	        // 渲染激活项左侧的红色指示边线
	        &::before {
	          content: ' ';
	          display: block;
	          width: 3px;
	          height: 30px;
	          background-color: #c00000;
	          position: absolute;
	          transform: translateY(50%);
	        }
	      }
	    }
	  }
	}
	
	.cate-lv2-title {
		text-align: left;
		font-size: 16px;
		font-weight: bold;
		margin: 40rpx 0 20rpx 40rpx;
	}
	
	
	.cate-lv3-list {
	  display: flex;
	  flex-wrap: wrap;
	
	  .cate-lv3-item {
		width: 33.33%;
		margin-bottom: 10px;
		display: flex;
		flex-direction: column;
		align-items: center;
		image {
		  width: 60px;
		  height: 60px;
		}
	
		text {
		  font-size: 12px;
		}
	  }
	}
</style>
